1. Field of the Invention
The invention relates in general to hoist ring assemblies and, in particular, to an improved high strength, low cost, self-contained safety hoist ring which can be assembled and disassembled without the use of tools.
2. Description of the Prior Art
Hoist ring assemblies have been widely used throughout industry to provide for quick attachment to heavy objects desired to be lifted by such tools as cranes and jacks. Hoist ring assemblies are generally considered to be critical safety items because if a failure occurs, a heavy object may be dropped resulting in damage to people, the object, and its surroundings.
There are a variety of hoist ring assemblies having different swivel capabilities for particular applications. One variety is capable of swiveling throughout a complete 360 degree arc, and at the same time capable of being swung throughout an arc of substantially 180 degrees in a direction perpendicular to the 360 degree swivel arc, irrespective of the manner in which the hoist ring is attached to the load. A hoist ring assembly having this swiveling capability is herein referred to as a safety hoist ring.
For economic reasons it is desirable to produce safety hoist rings having a minimal number of easily formed parts. Previous safety hoist rings generally included numerous parts. See, for example, Tsui et al., U.S. Pat. No. 4,705,422, which discloses a safety hoist ring comprising 10 parts. Ease and speed of assembly and disassembly have not been a design priority with many prior safety hoist rings. See, for example, U.S. Pat. No. 4,705,422, which discloses a safety hoist ring which includes three snap rings which require the use of a snap ring tool to assemble and disassemble the hoist ring. Those concerned with these problems recognize the need for an improved, lower cost, safety hoist ring consisting of a minimum number of parts that can be easily assembled and disassembled without the need of special tools.
These and other difficulties of the prior art have been overcome according to the present invention.